1949 Cub Electrical rebuild

[Jude]

Thanks, all cleaned up and hopefully ready to go. I plan to install this afternoon with a new wiring harness.
Do I need to polarize the generator, and if so, how?
It is a 3 brush with cutout relay.

[Bob McCarty]

To polarize the gen: viewtopic.php?f=140&t=56748

[Jude]

Thanks,
Another question: How do identify the terminals on the ammeter? I know one goes to the starter, and the other to the fuse and the cutout relay, but which is which?

[Glen]

Hi,
Below is the wiring diagram for a 1949 Cub, with a magneto.
When the battery is connected, turn on the lights, the ammeter should show discharge. If it showing charge, change the wires on the ammeter to the opposite posts. It should show discharge then.
When the engine is running, check the generator output on the ammeter, it should show charge, when the engine is above slow idle speed.
The 1949 Cub owner's manual on here tells how to use the 4 position charge and light switch, on page 34.

The diagram below doesn't show the magneto or the wire for the magneto. The magneto uses an ignition switch with 1 post for a wire to connect to it. The wire goes to the small post on the side of the magneto.
The switch grounds the magneto to stop the engine.
Don't connect any battery power to the magneto if it using the original style coil in the top of it.
Below are pictures from TM Tractor Parts showing the original style ignition switch for a 1949 Cub.
http://www.tmtractor.com/tm-tractor/gel ... ng_001.htm

I have seen new ones for sale online in the past.
TM Tractor Parts sells the newer style switches also, if you need to buy a switch.

[Bill V in Md]

Thanks,
Another question: How do identify the terminals on the ammeter? I know one goes to the starter, and the other to the fuse and the cutout relay, but which is which?

Below is a photo of the actual ammeter wiring on a 48 Cub, 6v, magneto with generator and cutout relay. As you can see, there are two wires on the right terminal of the ammeter and one wire on the left ammeter terminal. Also, as you can see, the black wire on the right ammeter terminal goes to the fuse on the 4-position light switch. The other wire on the right ammeter terminal goes to the generator relay cutout (BAT Terminal). The wire on the left terminal of the ammeter goes to the starter switch. Hope this helps.

[Jude]

Thanks!
Is there a way to test the ammeter before I complete the install?

[Bill V in Md]

I have not done this, but you should be able to use jumper wires to connect the ammeter in series between the 6v battery and the Cub’s 6v light bulb. When the bulb lights up, the amp gage should show the current draw. The bulbs are rated 24 watts, so current draw should be about 4 amps.